We believe in a God incarnate. The fact that the eternal Word was human flesh in Jesus of Nazareth centers our faith.

Hence Christians, and especially Roman Catholics, seem to celebrate the human body endlessly. We cherish sacraments that affirm God’s presence in our births and dyings, our confession of sin, and marking of commitment. Our feast days are remembrances of deaths, births, and even conceptions.

Not only do we celebrate when Jesus was born; we commemorate those precise moments of space and time when he was conceived and circumcised. And after we honor the Holy Spirit and the Blessed Trinity at this time of the church year, our rituals turn to Christ’s glorious flesh. We celebrate his heart as sacred, his blood as precious and his body as transfigured.

Christians cannot be other than a people that honors the body. True, we are quite aware of its frailty and fate, but its ontological goodness remains an inescapable fact. Thomas Aquinas insisted that the body could never be the ultimate source or immediate cause of evil. Otherwise, how could the incarnation have occurred? How could Christ have been a human body?

The feast of Corpus Christi—now called the Body and Blood of Christ—has had, over centuries, special associations. Its origins seem to be in the thirteenth century’s cultic response to eucharistic controversies of the previous century. Until then, focus on the Eucharist centered on the sacrificial action of the sacrament rather than on the real presence apart from the Mass. As the reception of Communion became rarer among the body of believers, the impulse to adore from afar was intensified through devotion to the enthroned sacrament. The piety of holy men and women, including the likes of Aquinas, also called attention to the Blessed Sacrament until it became an official celebration of the church at the beginning of the fourteenth century.

Eucharistic processions were found as early as then. The great slow march of believers became a splendor of physicality, not only in solemn parade but also in a panoply of sensible delight: sound in song, color in vestment, fragrance of incense and flower.

Whatever its historical genesis and development, the feast of the Body and Blood of Christ has a thematic reach that touches the core meaning of our salvation and the furthest extent of our mission.

First, it is a celebration of Jesus Christ’s body, a body like our own, genetically coded, conditioned by birth, developing through life, and undergoing the terrible relinquishment of death. It is a celebration of his body, moreover, which he identified with bread and wine in his Last Supper, given to us as the food of faith. We literally take into our own bodies the body of the Savior. This re-enacts the Incarnation: God once again takes human flesh. We are the indwelling.

Communion also re-enacts our redemption. Each time we celebrate this sacrament we embody the covenant of Christ, wherein God sees in us anew the flesh of Jesus. It was not by the “blood of goats and calves, but by his own blood” that our redemption was achieved and our consciences cleansed. Jesus Christ, “body, blood, soul, and divinity,” becomes substantially one with our bodies as our very food and sustenance. Thus God beholds each of us and sees the beloved Son sent to save us.

But it is not only God’s vision of us that is affected. Our own vision of ourselves and of each other is transformed. If we fully penetrate this mystery, we are empowered to see each other as God sees us: as the body and blood of Christ.

The consecration at the Eucharist is marked by the words, “This is my body. ... This is my blood.” Through our Communion, the words apply to each of us. Transubstantiation, then, applies not only to the appearances of bread and wine, it also applies to the appearances of human flesh.

Perhaps this is the eucharistic meaning of Jesus’ parable of the last judgment in Matthew 25. When all the nations of the world are gathered together, the Son of Man utters those strange words: “Insofar as you did it to the least of these, you have done it to me.” In the body of the prisoner or stranger, the hungry or the naked, the disconsolate or the sick, a second transubstantiation has taken place. Christ has said over the least of us: “This is my body.”

In his sermon “The Weight of Glory,” CS Lewis wrote: “Next to the Blessed Sacrament itself, your neighbor is the holiest object presented to your senses.” Christ’s body is as hidden in the least of us as it is under the appearances of bread and wine. Both require an uncommon and daring faith.

When we labor for human rights, when we shelter the poor, when we dismantle the bombs, when we protect the unborn, when we reach out to the criminal, we do these things not as political activists or social workers. We do them not as liberals or conservatives. We do them as people who worship the incarnate God.

The body and blood of Christ is not only our redemption. It is our task.